1. Field of the Invention
The present invention relates to a fluid drain valve.
More particularly, but not exclusively, the present invention relates to a low-profile low-restriction drain valve for use on fluid reservoirs to drain the reservoir content.
The drain valve of the present invention is particularly but not exclusively intended to replace drain plugs provided on the reservoirs of fluid lubricated, cooled or heated machines or components such as combustion engines, to facilitate fluid drainage and replacement.
2. Brief Description of the Prior Art
It is current practice for one of ordinary skill in the art of fluid handling to use a valve to extract fluid from a reservoir in order to properly direct this fluid into a collecting vessel, without splashing the attendant and the immediate periphery. However, there is still a number of fluid lubricated or cooled machines or components such as internal combustion engines, gear boxes, electrical machines, heat exchangers etc. that require periodical drainage and replacement of the fluid in a reservoir, but are supplied by the manufacturer with a simple drain plug threaded in an opening provided in the bottom wall of the reservoir. Removal of the drain plug to drain the fluid is thus highly subject to splashing and dirtying of the maintenance person, tools and peripheral environment. For example, a car owner changing motor oil in his driveway is subject to splashing of hot oil on his hands and tools, and possibly on the driveway surface, thus requiring extensive cleaning and possibly causing injuries to users and permanent damage to the driveway surface. Moreover, the plug being a loose part can be lost causing troubles, delays and costs since the specific replacement part can be hard to obtain. Canadian patent application No. 2,078,945 by Ackerman published in 1993 shows such a drain plug for use on motor vehicles.
A certain number of drain valve types are known in the prior art that could be installed in the threaded drain opening of the fluid reservoir to at least reduce some of the drawbacks inherent to the use of a drain plug. Such a drain valve is disclosed by Laue in U.S. Pat. No 2,474,430 issued in 1949. The valve comprises an externally and internally threaded body receiving a threaded plug provided with a handle for manual operation. Nevertheless, the handle being located on the fluid outlet path, sputtering occurs and the user""s hand is contacted by the fluid. Moreover, since the plug is designed to extend into the body beyond the opening of the reservoir, the original diameter of the opening is further reduced by the addition of the wall thickness of the plug to that of the body.
In U.S. Pat. No. 3,727,638 (Zarembaxe2x80x941973), U.S. Pat. No. 3,948,481 (Pollockxe2x80x941976) and U.S. Pat. No. 4,025,048 (Tibbitsxe2x80x941977), although fluid flow is properly oriented for a clean and neat operation, effective opening size is still further reduced with respect to the original opening diameter, which dramatically increases the time required to drain all the fluid contained in the reservoir. Furthermore, the valves in Pollock and Tibbits are closed by unscrewing the knob to extend away from the bottom wall of the reservoir, creating an excessive overall profile height which causes risks of impact by obstacles along the road and potentially spillage and engine damage.
Although it is not intended for use as a drain valve fitting in a threaded opening, the nozzle disclosed in U.S. Pat. 627,073 (Cliffxe2x80x941899) presents some interest. Indeed, a cap provided with a centre opening is screwed on the external threads of a body provided with semi-circular outlet ports. When the cap is unscrewed fluid escapes from the semi-circular outlets through the cap internal cavity and finally through the centre opening. When the cap is screwed, the centre opening is closed by the gasket lined solid wall portion extending between the semi-circular outlet ports of the body, thus preventing fluid spillage. Such a closure concept can be adapted to provide a low profile drain valve. However the body is not adapted to fit into a threaded hole and very significant restriction to fluid flow occurs in the body and cap outlet ports. In addition, seal mounting is not appropriate to facilitate periodic replacement and to limit compression. Furthermore manufacturing is expensive since it requires metal casting and complex and extensive machining.
There is thus a need for a low-profile low-restriction drain valve that can fit into an existing threaded drain opening of a fluid reservoir to replace a plug and provide a neat fluid stream and avoid sputtering and contacting with hands and tools.
An object of the present invention is therefor to provide a drain valve which overcomes the limitations and drawbacks of the above mentioned solutions of the prior art.
More specifically, in accordance with the invention as broadly claimed, there is provided a drain valve for use with a fluid reservoir having a drain opening, comprising a valve body, a cap and a at least one perforation-sealing member. The valve body has a tubular shank for installation in the drain opening and defining a fluid ingress, and a tubular head portion generally coaxial with the tubular shank and defining a chamber in communication with the fluid ingress and having a cross sectional area larger than a cross sectional area of the fluid ingress. The valve body also comprises an inner transverse wall extending across the chamber and having at least one fluid flow perforation, and a distal end opposite to the shank. The cap is movably assembled to the distal end of the tubular head portion between open and closed positions. This cap defines a fluid egress which, in the open position of the cap, is in communication with the above mentioned at least one perforation to permit draining of fluid from the reservoir. The perforation-sealing member is interposed between the cap and the tubular head portion and, in the closed position of the cap, seals the above mentioned at least one perforation to prevent draining of fluid from the reservoir.
Preferably, to prevent restriction to the fluid flow caused by the drain valve, the above mentioned at least one perforation has a cross sectional area substantially equal to or larger than a cross sectional area of the fluid ingress, and the fluid egress has a cross sectional area substantially equal to or larger than the cross sectional area of the at least one perforation.
In accordance with other preferred embodiments of the drain valve:
the drain opening is threaded, the tubular shank is externally threaded for screwing into the threaded drain opening, and the tubular head portion comprises external flank faces for tightening or loosening the externally threaded tubular shank in the threaded drain opening by means of a tool;
the drain valve further comprises an annular seal member interposed between an outer surface of the tubular head portion and an outer surface of the fluid reservoir, this annular seal member being compressed between these outer surfaces of the tubular head portion and the fluid reservoir when the externally threaded tubular shank is tightened in the threaded drain opening;
the drain fluid ingress enlarges into the chamber through a frusto-conical wall section;
the drain valve is a low-profile low-restriction drain valve, the inner transverse wall is located at the distal end of the tubular head portion, the at least one perforation of the inner transverse wall comprises a set of peripherally distributed perforations, the tubular head portion is cylindrical and externally threaded, the cap comprises an internally threaded cylindrical section screwed onto the cylindrical externally threaded tubular head portion and an annular inward flange at a distal end of the internally threaded cylindrical section, and the at least one perforation sealing member is annular and interposed between the annular inward flange and a peripheral portion of the inner transverse wall in which the peripherally distributed perforations are made;
the tubular head portion is externally threaded but comprises proximal, external tool-engaging flank faces;
the tubular head portion is externally threaded and comprises external tool-engaging flank faces made in the external threaded surface of the tubular head portion, and the externally threaded tubular head section comprises a distal, external threaded border with no tool-engaging flank faces;
the drain valve is a low-profile low-restriction drain valve; the inner transverse wall is located in the chamber remote from the distal end of the tubular head portion; the tubular head portion is cylindrical, internally threaded, and comprises a distal annular edge surface; the cap is cylindrical, externally threaded and screwed in the internally threaded tubular head portion; the at least one perforation of the inner transverse wall comprises a set of peripherally distributed perforations; the externally threaded cap comprises a proximal externally threaded cap section, a distal unthreaded cap section, an external annular shoulder between the proximal externally threaded cap section and the distal unthreaded cap section, and a proximal annular edge surface; and the at least one perforation-sealing member comprises a first annular seal member between the external annular shoulder of the externally threaded cap and the distal annular edge surface of the tubular head portion, and a second seal member between the proximal annular edge surface of the externally threaded cap and the inner transverse wall;
to avoid back pressure, the fluid egress has a cross sectional area larger than a cross sectional area of the at least one perforation;
the chamber, the at least one perforation and the fluid egress have respective cross sectional areas which create a Venturi effect within the drain valve when the cap is in its open position;
the at least one perforation of the inner transverse wall comprises a set of peripherally distributed perforations;
the cap comprises: a bottom surface with a diameter which is large with respect to a diameter of the egress, this egress opening through the bottom surface of the cap; and a cylindrical section with external tool-engaging flank faces sufficiently distant from the fluid egress as to prevent a fluid stream from contacting a tool or a user""s hand;
the fluid egress comprises means for receiving a drain tube;
the at least one perforation has cross sectional area which is less than 50% of a total area of the inner transverse wall; and
the drain valve further comprises abutment faces controlling compression of the at least one perforation-sealing member.